import java.util.*;

public aspect Persistence {

  private Set dirtyObjects = new HashSet();

  // this pointcut identifies the domain objects
  pointcut domain(): within(domain.*);

  // every time an instance variable of a domain object o
  // is set, the object becomes dirty and needs to be added
  // to the dirtyObjects Set.
  pointcut dirty(Object o):
      domain() && this(o) && set(* *.*);

  // this pointcut specifies all the transactional methods,
  // after which the set of dirty objects must be written to
  // the database.
  pointcut transactional(): call(* Main.createCustomer(..));

  // add the now dirty object o to dirtyObjects
  after(Object o): dirty(o) {
    dirtyObjects.add(o);
  }

  // a transactional method has completed; write all the dirty
  // objects to the database...
  after() returning: transactional() {
    for (Iterator i = dirtyObjects.iterator();i.hasNext();) {
      writeToDB(i.next());
    }
    dirtyObjects.clear();
  }

  private void writeToDB(Object o) {
    System.err.println("Writing " + o + " to database...");
  }
}